Smoke generator



APril 1961 F. RIGALI SMOKE GENERATOR Filed May l5 1957 3 Sheets-Sheet 1 V/BRA TOR 27 ATTORNEY April 1961 J. F. RlGALl 2,977,954

SMOKE GENERATOR Filed May 15, 1957 3 Sheets-Sheet a I! mg] f i /03 q4 INVENTOR 26 9 4 J05 40/7 ffl/jafi' BY Maw SMOKE GENERATOR Joseph F. Rigali, Kansas City, Mo., assignor to Koch Supplies Inc., Kansas City, Mo, a corporation oi Missouri Filed May 15, 1957, Ser. No. 659,298

11 Claims. (Cl. 126-595) This invention relates to a smoke generator for supplying smoke used to treat various food products, and has for its principal object to provide an apparatus for generating a high quality smoke utilizing wood particles such as sawdust or small wood chips.

Wood particles offer a readily available and less expensive supply of those woods that provide the most desirable smoke flavors, but previous generators for utilizing wood particles have not been completely satisfactory, the principal difficulty being to obtain a high quality smoke, comparatively free from objectionable matter. The primary causes of such difiiculty are inability of previous generators to feed the wood particles uniformly from a supply into a burning zone and to sufiiciently control the burning necessary for generating the high quality smoke. If the burning rate is too high,

with total combustion taking place, little or no smoke is produced, and if the burning rate is too low, objec-- tionable components of the wood will distill off and be carried along with the smoke to the place of treatment, with the result that the smoked product has objectionable odor and taste.

The present invention overcomes these difliculties by providing a smoke generator with means for accurately controlling the rate of feed of the wood particles in accordance with a positive and controlled air supply to maintain burning conditions necessary for generating a high quality smoke in the volume which is required.

Other objects of the invention are to maintain a com bustion zone of uniform area and depth and to control the heat which is generated to that necessary for main taining depth of the burning zone; to provide for vibration of the grate which supports the bed of wood particles at a controlled rate to eiiect continuous discharge of the ash from the burning zone and replacement by sawdust from the means of supply in accordance with a definite volume of air; and to provide the generator with an airtight ash compartment to assure passage of all the air being supplied for combustion by way of the grate into the burning zone, thereby maintaining uniform combustion.

It is also an object to provide the burning zone of the generator with heating elements for establishing initial combustion when starting up the generator and which heating elements are turned off with energization of the air supply to continue combustion solely by the heat of burning and the air supply.

Further objects are to provide a smoke generator that is of simple and relatively inexpensive construction and Patented Apr. 4, 1961 2 erator constructed in accordance with the present invention.

Fig. 2 is a similar perspective section of the generator with the section being taken at right angles to the section "of Fig. 1.

Fig. 3 is a fragmentary, perspective, view of the discharge end of the sawdust supply hopper of the generator.

Fig. 4 is a perspective view of the combustion chamber, particularly illustrating the heating elements for establishing initial combustion.

Fig. 5 is a perspective View of the grate and support therefor.

Fig. 6 is a perspective view of the ash pan or drawer.

Fig. 7 is a diagrammatic view of the electrical circuits for supplying electric current to the heating elements, the air supply blower, the smoke circulating blower, and the vibrator, particularly illustrating the arrangement of the switches in the circuitry to control the operating sequences of the electrically operated mechanisms. I

Fig. 8 is an enlarged section through the combustion chamber, the upper portion of the ash compartment, and the discharge end of the supply hopper and indicating the zone of burning.

Fig. 9 is a horizontal section through the upper portion of the smoke chamber and supply hopper.

Referring more in detail to the drawings:

1 designates a smoke generator constructed in accordance with the present invention for generating smoke utilizing wood particles such as sawdust or chips which are normally waste material during manufacture of wood products from woods that are most desirable for creating smoke used in the treatment of various food products. I I

The generator 1 includes a casing 2, preferably constructed of sheet metal or other fire resistant material capable of transmitting vibrations. The casing illustrated is of rectangular form and has side walls 3, 4, 5 and 6, I

a slightly inset top 7, and a bottom 8 which is inset upwardly from the lower end of the casing to provide an air space 9 thereunder. Three sides of the bottom 8 are spaced from the corresponding side walls of the casing, for example, the side walls 3, 4 and 6, to provide air inlets 10, 11 and 12 from the air space 9 into the lower end of the casing. Extending upwardly from the bottom 8 alongside the openings l0, l1 and 12 are walls l3, l4 and 15 of an ash compartment 16 having a closed top 17. The sides 13 and 14 and the top 17 connect with the outer wall5 of the casing, as best shown in Fig. l, and cooperate with the bottom in surrounding an opening 18 in the side wall 5. The opening 18 is normally closed by a door 19 that is suitably attached to the side wall for access to the ash compartment 16 when inserting and removing an ash drawer 20. The top, side walls and bottom of the ash compartment are connected together and to the casing wall 5 by means of substantially airtight joints and a gasket 21 preferably surrounds the door opening 18 to seal around the door, so that the ash compartment is substantially airtight with the exception of an opening 22 in the top 17 and an opening 23 offset laterally of the opening 22, for purposes later described. g Air is admitted into the space 9 for passage through the openings 10, 11 and 12, and corresponding vertical passageways 24- that are provided between the walls of the ash compartment and the corresponding walls of the casing for fiow into a smoke compartment 25 to mix with the smoke to be generated. The bottom edges of the casing Walls are offset upwardly intermediate the corners 26 to provide air inlets 27 between corner legs 28 on which the casing is supported. Since the invention contemplates vibrating the casing, it is essential that the legs 28 all firmly engage the fioor and, therefore, the legs are provided with adjustable feet 29.

Mounted in the ash compartment in laterally spaced apart guide rails and 31 is a grate-plate 32 having a plurality of apertures 33 at one end thereof in direct registry with the opening 22. The other end of the plate 32 extends forwardly in the direction of the door opening 18 and terminates in a depending flange 34 that serves as a handle by which the plate may be readily withdrawn through the door opening. The guides 30 and 31 are of channel shaped cross section and each has upper and lower flanges 35 and 36 connected by a web 37 to form grooves 38 in which side edges 39 of the plate are mounted. The guides are supported from the side Walls 13 and 14 of the ash compartment by braces 41 and 42 that connect with the side walls 13 and 14 a suflicient distance above the bottom thereof to pass the ash drawer 20 thereunder. The ash drawer 20 comprises 'a bottom 43, a front 44 of sufficient size to substantially close off the end of the ash compartment when the door is open, and relatively shallower side walls 45 and 46 that are connected with a correspondingly shallow rear wall 47 to avoid interference with the braces 41 and 42.

The ash drawer has a plate 48 extending between the side walls and sloping from the inside of the front wall 44 as shown in Fig. l to join with the bottom 43 of the drawer. The plate 48 thus forms a brace in promoting rigidity of the drawer and to facilitate removal of the ashes when the drawer is to be emptied. The outer side of the front wall may be provided with a handle 49 to facilitate manipulation of the drawer.

Carried directly upon the top 17 of the ash compartment is a combustion chamber 50 which receives sawdust from an upwardly disposed supply hopper 51. The combustion chamber 58 has an upwardly and outwardly flaring annular wall portion 52 that extends from a cylindrical neck portion 53, the neck portion 53 being of a diameter to fit within the opening 22 and to depend into substantially close but slightly spaced relation with the apertured portion of the grate-plate 32. The combustion chamber is supported by a collar 54 that encircles the neck portion 53 and has an annular flange 55 seating on the top 17 of the ash compartment in encircling relation with the opening 22 therein. Also encircling the neck portion of the ash compartment near the juncture of the conical wall portion therewith is a lower heater 56 that cooperates with an upper heater 57 which is spaced from the lower heater by a ring 58 attached to the conical wall portion 52, as best shown in Fig. 5. The heaters 56 and 57 contain electrical elements that are supplied with an electrical current through conductors 59 and 60 (Fig. 7).

The supply hopper 51 also includes a conical wall portion 61 having an upper diameter of a size to fit within an opening 62 provided in the inset top 7 for support thereon by means of an annular flange 63 that is formed on the open upper end of the hopper and bears upon the upper face of the top 7, as best shown in Figs. 1 and 2. The lower end of the conical wall of the hopper terminates in a cylindrical portion 64 of less diameter than the upper diameter of the combustion chamber to provide an annular passageway 65 through which smoke passes from the combustion chamber into the smoke compartment of the casing. The lower end of the cylindrical portion of the hopper carries an inwardly and downwardly extending flange portion 66 which encircles a discharge opening 67 to better direct the sawdust toward the center of the combustion chamber 50, the discharge opening 67 being located a sutficient distance below the rim 68 of the combustion chamber to stop the flow of sawdust when the sawdust in the combustion chamber reaches the level of the outlet, thereby providing for automatic feed of sawdust from the hopper into the combustion chamber as the sawdust is consumed therein and the ash discharged through the apertured plate, as later to be described.

In order to control flow of the sawdust through the opening 67, the flange portion 66 carries a plurality of downwardly converging vibratory rods or wires 69 that have their terminals spaced apart in the axis of the combustion chamber, to pass therebetween a vertical vibrating member 70, as best shown in Figs. 1, 2 and 8. T he member 78 includes a rod 71 that extends from the upper portion of the hopper 51 to the grate-plate. The lower end 71' of the rod preferably rests upon the grateplate and the upper portion of the rod is supported by arms 72 that are carried thereby and the ends engage the conical wall portions of the hopper. Also mounted on the rod within the cylindrical portion of the hopper is an agitator comprising radial vanes 73 that are set at a slight angle and have their ends spaced from the hopper so that they move freely with vibration of the rod in moving the sawdust downwardly into the combustion chamber.

The combustion zone to be maintained in the combustion chamber extends from a point slightly below the level of the lowermost heater 56 to a level above the upper heater 57, but spaced a distance below the terminals of the rods 69, the upper and lower levels being indicated by the dotted lines designated 74 and 75, Fig. 8. Positioned within the zone of combustion are vibrating rods 76 having ends 77 attached to the combustion chamber substantially at the juncture of the cylindrical and conical portions thereof and which extend from the point of connection upwardly and across the zone of combustion to terminate in spaced relation with the opposite side wall in fingers 78. The finger ends of the rods 76 vibrate within the upper zone of combustion to facilitate feeding and spreading of the sawdust from the upper portion of the combustion chamber into the zone of combustion as the ash from the lower zone of combustion is discharged through the apertures 33 of the grate-plate 32 into the ash drawer.

The upper end of the casing is closed by a cover 79 that extends over the open upper end of the hopper and and has a depending flange 80 fitting over the upper edges of the side walls of the casing. The cover may be provided with handles 81 by which it may be engaged when it is necessary to remove the cover, as when filling the hopper with sawdust. A gasket 82 is preferably placed under the flange 63 of the hopper to seal around the hopper. The hopper may be fastened down on the top of the casing by clamps (not shown).

Access is provided to the smoke compartment for inspection of the feed of the sawdust into the combustion chamber and to clean out the smoke compartment through a door opening 83 that is located in the side wall 5 of the casing directly above the door opening 18 to the ash compartment, the door opening 83 being closed by a door 84 similar to the door 19 previously described and which seats against a gasket 85, as shown in Fig. 1.

To prevent fly ash from dropping on the floor through the passageways 24, the rear side wall of the casing carries a baflie 86 that extends transversely thereof and which slopes downwardly toward the top of the ash compartment but is spaced therefrom as indicated at 87 to provide outlet for air from the passageway at the rear of the ash compartment. The side walls 3 and 4 carry similar bafiles 88 and 89 located above the baffle 86 to cover the passageways 24 at the sides of the ash compartment but which are spaced a suflicient distance from the top thereof to provide air outlets 90 and 91 into the smoke compartment.

The casing of the generator preferably includes an extension 92 thereof for enclosing an upper blower 93 (if desired) and a lower blower 94. The extension 92 has sides 95 and 96 that extend from the rear side of the casing in substantial alignment with the side walls 3 and 4. The sides of the extension 95 and 96 are connected across the rear of the casing by a wall 97. The sides 95 and 96 and the wall 97 terminate above the floor and cooperate with the rear wall of the casing to form an upwardly extending duct 98 for supplying air to the blowers 93 and 94 through the open bottom 99 of the extension. The blowers 93 and 94, together with their motors 100 and 101, are suitably carried within the extension. The lower blower 94 has an outlet 102 connected through a valve 103 with a duct 104 extending through the wall 6 at a point above the baffle 86 to terminate in elbow portion 105 which connects with the opening 23 whereby combustion supporting air is supplied under pressure to the ash compartment for discharge through the apertures of the grate and through the cylindrical neck portion 53 of the combustion chamber 50 into the zone of combustion. The upper blower 93 is for circulating the smoke from the smoke compartment to the smokehouse in which food products or the like are treated with the smoke. In the illustrated instance, the discharge neck 106 of the blower is supported in the wall 6 of the casing and discharges into the flaring end 107 of an eductor nozzle 108 by which smoke and air is drawn from the smoke compartment through an outer duct 109 in which the nozzle 108 extends. The duct 109 connects with a venturi portion 110 through which the nozzle discharges, as shown in Fig. 9. The venturi in turn connects with the supply duct 111 leading to the Smokehouse. If the smokehouse is provided with a smoke circulating system, then the blower 93 and eductor nozzle 108 may be omitted and the smoke conduit 111 is directly cortnected to the smoke chamber.

As above stated, the sawdust is caused to be fed from the hopper 51 into the combustion chamber 50 and the ash from the combustion chamber 50 is discharged responsive to vibrations which are applied to the casing, preferably through the bottom of the ash compartment. A vibrator 112 is therefore secured to the bottom 8 of the ash compartment by means of a bracket 113 rigidly attached thereto. The vibrator is thus suspended within the air space 9 and when energized causes the bottom 8 to vibrate, which vibrations travel upwardly through the sides 13 and 14 of the ash compartment and through the braces 41 and 42 which carry the guide rails 30 and 31 and the grate-plate 32 whereby the vibrations are concentrated on the grate-plate 32 to effect a movement thereof necessary to shake down and discharge the ash from the combustion chamber and into the ash drawer 20 to be replaced by the recently burned sawdust, which in turn is replaced by the sawdust from the upper part of the combustion chamber. Vibrations are also trans mitted through the metal of the casing walls to the saw-' dust hopper 51 to effect vibration thereof for feeding the sawdust from the hopper 51 into the combustion chamber 50. These vibrations are supplemented by the vibrating rods 69 that are attached to the discharge end of the hopper and the vibrations of the member 70. Vibrations 'are also transmitted to the combustion chamber by way of the side walls 13 and 14 and top 17 of the ash compartment to maintain the sawdust therein in constant movement so as to facilitate contact of the sawdust with the combustion supporting air supplied through the grate compartment. Vibration of the combustion chamber 50 produces vibration in the rods 76 to further promote movement of the particles in the combustion zone to maintain sufiicient looseness for contact of the particles with the combustion supporting air.

The back wall 97 of the extension 92 of the casing constitutes a panel for mounting switches 114, 115 and 116 and a vibration controller. in the form of a rheostat 117, all of which form a part of the electrical system for supplying current to motors 100 and 1 of the blowers 93 and 94, heaters 56 and 57 and vibrator 112, as shown in Fig. 7. The circuitry includes line wires 113 and 119 that are suitably connected with an electrical service to supply current to pairs of conductors 120 and 121 leading to the motor 100, 122 and 123 leading to the vibrator, 59 and 60 leading to the heater-s 56 and 57, and a conductor 124 which connects with the one terminal of the motor 101, the other terminal of the motor 101 being connected with the conductor 59. The

switches 114 and '115 controlling the motor and controlling current to the vibrator 112 may be single pole switches to independently and directly open and close current to the motor 1110 and vibrator 112. However, the heaters 56 and 57 and the motor 101 are alternately operated, that is, when the heaters are energized, the circuit is opened to the motor 101, and vice versa. This is eiiected by providing the switch 116 with double contacts to connect the line wire 119 with one or the other of the conductors 60 and 124. If desired, the various circuits may be provided with signal lights 125 to indicate visibly whether or not the respective circuits are in operation.

Access is had to the valve 103 and motor 101 through an opening 126 that is closed by a door 127, while access to the motor 100 is best attained through removal of a cover 128 which closes the upper end of the extension 92.

Assuming that the generator is constructed and assembled as described, it is installed by connecting the smoke duct 111 with a smokehouse (not shown) and by making the necessary electrical connections with the service wires 11% and 119. If the smokehouse is equipped with its own circulating fan, then the blower 93, nozzle 193, duct 109, and venturi are omitted and the smoke conduit is directly connected with the collar 129.

The generator is charged by removing the cover 79 and pouring'wood particles such as sawdust or chips from those woods capable of giving the desired smoke flavor into the open top of the hopper 51. The wood particles fall through the opening 67 at the bottom of the hopper 51 and into the combustion chamber 50 to lodge upon the grate-plate 32. Continued inpour of the wood particles fills the combustion chamber 511 up to the level of the discharge opening 67 in the hopper. The flow into the combustion chamber is then automatically suspended, since the wood particles will not move upwardly on the exterior side of the flange 66. The wood particles now start to fill the sup-ply hopper up to a desired level, for example, as shown in Fig. 1. The wood particles till in and around the vibrating rod 76, rods 69, 76 and 71, vanes 73 and arms 72. The cover 79 is replaced. The switch 116 is then moved to close contact between the line conductor 119 and conductor 60, thereby establishing a flow of current from the line wires 11S and 119 by way of conductor 60, resistance elements of the heaters 56 and 57, and conductor 59. The heat generated by the heaters is transmitted to the wood particles through the points of the combustion chamber in contact with the heaters, to bring the wood particles to combustion temperature and establishing a ring of burning within the combustion chamber. As soon as combustion is started and becomes established, the switch 116 is moved to open circuit through the heaters and to establish connection of the conductor 124 with the line conductor 119. Current then flows to the motor 101 by way of the conductors 124 and 59 to operate the blower 94 which supplies air under pressure. Air from the blower 94 is discharged through the open valve 103 and duct 104 into the ash compartment 15 to build up the air pressure therein for discharge through the openings 33 of the grate-plate 32 for escape upwardly between the wood particles to supply air necessary to con-' tinue combustion of the wood particles initially started by the heaters 56 and 57. The volume of air is regulated by means of the valve 103 to supply only the air necessary to build up a zone of burning, as indicated between the dotted lines 74 and 75. The smoke which results moves through the spaces between the wood particles in the upper portion of the combustion chamber and is discharged through the annular passageway 65 into the smoke chamber.

To promote the flow of wood particles from the hopper into the combustion chamber as the wood particles are converted to ash, and to assist in discharge of the ash 7 through the apertures 33 of the grate-plate 32, the switch 115 is closed to activate the vibrator 112. With the vibrator in operation, vibrations are transmitted through the bracket 113, bottom 8 of the casing, sides 13-14, and top 17, of the ash compartment. The grate-plate 32, being supported solely by the arms 41 and 42 and directly from the side walls 13 and 14, receives the greatest force of the vibrations, so that the greatest effect of the vibrations is concentrated in the grate-plate, rod 71 that rests thereon, and vanes 73. Vibrations to the next degree are transmitted from the top 17 through the collar 54 and wall portions 52 and 53 of the combustion chamber. The rods 76, being attached directly to the wall of the combustion chamber, vibrate with their free ends 7? vibrating within the burning or combustion zone to promote looseness of the wood particles and flow of combustion air into contact therewith and to'displace the smoke from the burning particles into the smoke chamber. Vibrations are also transmitted through the walls 3:, 4, 5 and 6 of the casing to vibrate the Wall portions of the supply hopper and to effect vibration of the rods 6?, that are spaced about the discharge opening 67, to assist the vibrating rod 71 and vanes 73 in feeding the wood particles through the opening 67 for replacing wood particles as they become consumed and are discharged as ash through the apertures 33 of the grateplate into the ash drawer 20. The intensity of the vibrations are controlled by regulating the current through adjustment of the rheostat 117.

When the switch 114 is closed, the motor 190 is energized to operate the blower 93. The blower 93 discharges air under pressure through the nozzle 168, and the fiow of air aspirates smoke mixture from the smoke chamber by way of the open end of the duct 109, from where it is discharged through the venturi portion 111) at substantial velocity into the duct 111.

The air of the smoke mixture is drawn from the bottom space 9 through the vertical passageways 24 for discharge under the baffies 86, 88 and 89 into the smoke chamber.

The valve 103 and vibration controller or rheostat 117 are adjusted until the desired volume and quality of smoke is being produced, after which the vibrations and air supply remain constant as long as the characteristics of the wood particles do not change. However, change in the character of the wood particles may require some subsequent adjustment of the air and vibration controls to maintain the desired volume and quality of smoke constant. If a greater or less amount of smoke is needed for any given product that is treated in the Smokehouse, the volume is quickly adjusted to the proper amount merely by changing the air supply and rate of feed through manipulation of the valve 103 and vibration controller 117.

Any fly ash passing into and dropping out in the smoke chamber is deflected onto the top 17 of the ash compartment by means of the baflles 86, 88 and 8?. The fly ash may be removed from time to time by way of the door 84.

The ash drawer is removed upon opening the door 19 of the ash compartment and withdrawing the drawer through the opening 18. After emptying the ash drawer, it is returned to the ash compartment.

It may also be necessary to clean the grate-plate and this is readily effected before starting up the generator. The door 19 is opened and the grate-plate 32 is removed from the guide rails by gripping the flange 34 and pulling the plate outwardly through the door opening. Any ash and sawdust contained in the combustion chamber 59 discharges into the ash drawer upon removal of the grate-plate, to result in emptying out the burnt material from the combustion chamber preparatory to a new charge.

If the Smokehouse to which the generator is connected is equipped with its own circulating fan, then the smoke mixture is withdrawn directly through the collar 129.

From the foregoing, it is obvious that I have provided for generating smoke from wood particles wherein the wood particles are fed to a zone of combustion at a rate to keep the zone of combustion covered with unburned wood particles, and that the zone of combustion is localized and maintained stable by supplying the proper amount of combustion supporting air and in accordance with an adjustable feed of the wood particles.

What I claim and desire to secure by Letters Patent is:

1. In a smoke generator, a combustion chamber having an open top and an ash outlet at the bottom, a grate covering the ash outlet in said combustion chamber and having open apertures, means for automatically feeding a burnable material into the open top of the combustion chamber, means for supplying air under pressure through the open .apertures of the grate for maintaining a zone of combustion in the combustion chamber, means for vibrating the combustion chamber including the grate for discharging ash from under the zone of combustion and for effecting feed of material from the upper portion of the combustion chamber to the zone of combustion, vibratory members within the combustion chamber and each having one end fixed to a part of the combustion chamber and having free ends extending into the zone of combustion to vibrate with the combustion chamber for loosening the material for contact by the air, and means for controlling intensity of the vibrating means to regulate feed of the material.

2. In a smoke generator, a combustion chamber having an open top and an ash outlet at the bottom, a grate covering the ash outlet, means for automatically feeding a burnable material into the open top of the combustion chamber, means for supplying air under pressure through the grate for maintaining a zone of combustion in the combustion chamber, means for vibrating the combustion chamber including the grate for discharging ash from under the zone of combustion for effecting feed of material from the upper portion of the combustion chamber to the zone of combustion, vibratory members within the combustion chamber and each having one end fixed to a part of the combustion chamber to vibrate therewith and having free ends extending into the zone of combustion for loosening the material for contact by the air, means for controlling intensity of the vibrating means to regulate feed of the material, and means for .controlling the volume of air flow from said air supply means to cooperate with the feed of the material to maintain a substantially uniform constant burning level in the zone of combustion.

3. In a smoke generator, a combustion chamber having an ash outlet, a grate covering the ash outlet of the combustion chamber, means for supplying air through the grate to maintain a combustion zone within the combustion chamber, a hopper for containing a burnable material and having a discharge outlet into the combustion chamber, said outlet being adapted to be valved by rise and fall of material in the combustion chamber for maintaining automatically a given depth of material in the combustion chamber, vibratory means for transmitting vibrations to the material through the hopper, combustion chamber and grate for promoting feed of material from the hopper into the combustion chamber and into the combustion zone and discharge of ash from the combustion zone through the grate, means for regulating the vibrating means to control the feed of material, and means for controlling the air supply in accordance with the feed of said material to obtain a desired quality and volume of smoke.

4. A smoke generator including a casing providing a smoke compartment, said casing having a part for providing an ash compartment separate from the smoke compartment, a combustion chamber supported within the easing on said part of the casing which provides the ash compartment, said combustion chamber having an open top in connection with the smoke compartment and said combustion chamber having an ash outlet portion in connecg. tion with the ash compartment, a grate covering the ash outlet portion, means for supporting the grate from opposite sides of said part of the casing which provides the ash compartment, a vibrator attached to said ash compartment to vibrate the grate through said supporting means for discharging ash from the combustion chamber into the ash compartment, means for supplying air to the ash compartment for passage through the grate to maintain a bed of burning material Within the combustion chamber, and a hopper in the smoke compartment for- I contact with the burning material.

5. A smoke generator including a casing providing a smoke compartment, said casing having a part for providing an ash compartment separate from the smoke compartment, a combustion chamber supported within the casingon said part of the casing which provides the ash compartment, said combustion chamber having an open top in connection with the smoke compartment and said combustion chamber having an ash outlet portion in connection with the ash compartment, a grate covering the ash outlet portion, means for supporting the grate from opposite sides of said part of the casing which provides the ash compartment, a vibrator attached to said ash compartment to vibrate the grate through said supporting means for discharging ash from the combustion chamber into the ash compartment, means for supplying air to the ash compartment for passage through the grate to maintain a bed of burning material within the combustion chamber, a hopper in the smoke compartment for containing a burnable material and having a discharge outlet into the combustion chamber, said discharge outlet of the hopper being adapted to be valved by rise and fall of material in thecombustion chamber for maintaining automatically a depth of unburned material in covering contact with the burning material, an agitating means having support on the grate and extending upwardly through the combustion chamber and into the hopper for promoting feed of material into the combustion zone, and means for controlling the volume of the air supply in relation to the feed of material into the combustion chamber.

6. A smoke generator including a casing providing a smoke compartment, a vibrator connected with a part of the casing for vibrating the casing, a combustion chamber having an open top and an ash outlet, means for supporting the combustion chamber from said part of the casing to vibrate with the casing, a grate closing the ash outlet, means for supporting the grate from said part of the casing to vibrate the grate for discharging ash from a zone of combustion in the combustion chamber, means for supplying the combustion chamber with air under pressure to maintain combustion, a hopper within the smoke compartment for containing a burnable material and having a discharge into the open top of the combustion chamber, said discharge of the hopper being adapted to be valved by rise and fall of material in the combustion chamber for maintaining automatically a given depth of material in the combustion chamber in covering relation with the zone of combustion, an agitating means having support on the grate and extending up- Wardly through the combustion chamber and into the hopper to receive vibrations from the grate for promoting feed of material from the hopper into the combustion chamber, means for controlling the volume of the air supply, and means for controlling the vibrator to maintain the feed of the material in accordance with the air supply for generating the quality of smoke as needed.

7. A smoke generator including a casing providing a smoke compartment, a combustion chamber in said casing and having an open top in connection with the smoke compartment, said combustion chamber having an ash outlet, a grate covering the ash outlet, a hopper suspended within the casing for containing a burnable material and having a discharge into the open top of the combustion chamber, said discharge of the hopper being adapted to be valved by rise and fall of material in the combustion chamber for maintaining automatically a given depth of material in the combustion chamber, heating means encircling the combustion chamber at a point below the discharge of the hopper for initially starting a zone of combustion at the level of the heating means, means supplying air under pressure through the grate for sustaining combustion, means for vibrating the grate for discharging ash from the combustion zone and feeding material from the upper portion of the combustion chamber into the zone of combustion for replacement by material from the hopper, an agitating element extending through the combustion chamber and into the hopper and having support on the grate to receive vibrations from the grate for promoting feed of said material into the zone of combustion, means for controlling intensity of the vibrating means to vary the feed, and means for controlling the volume of air flow from said air supply means to cooperate with the feed of the material for maintaining quality of the smoke.

8. In a smoke generator, a combustion chamber having an open top for passage of smoke from the combustion chamber, said combustion chamber having an ash outlet, a hopper for containing wood particles and having a discharge into the open top of the combustion chambers, fingers each having an end fixed to the hopper and a free end extending across the discharge of the hopper and into the combustion chamber to vibrate with vibration of the hopper to facilitate feed of wood particles from the hopper into the combustion chamber, means for supplying air under pressure through the ash outlet for'maintaining a zone of combustion within the combustion chamber covered by the wood particles fed into the combustion chamber, fingers having an end fixed to the combustion chamber and free ends extending into the zone of combustion to vibrate with the combustion chamber, and means for vibrating the hopper and combustion chamber together with the fingers therein to facilitate movement of the wood particles into the zone of combustion for replacement by Wood particles from the hopper and for discharge of ash from the zone of combustion.

9. A smoke generator including a casing having side walls and a top, an ash compartment having side walls spaced from side walls of the casing to provide air passages therebetween and having a top and a bottom providing a substantially airtight compartment separated from a smoke compartment in the upper portion of the casing, an open top combustion chamber within the casing and having a wall flaring upwardly and outwardly in encircling relation with an opening in the top of the ash compartment, an apertured grate covering the opening in the ash compartment to control passage of ash from the combustion chamber and air into the combustion chamber, a hopper supported in the smoke compartment of the casing and having a discharge neck suspended within the open top of the combustion chamber for directing flow of wood particles into the combustion chamber, said flow being controlled by rise and fall of the wood particles in the combustion chamber to and from contact with the discharge neck, means for supplying air under pressure to the ash compartment for discharge through the apertures of the grate to maintain a zone of combustion within the combustion chamber, a vibrator fixed to the bottom of the ash compartment, supports attached to opposite side Walls of the ash compartment and carrying guide rails to carry the grate and to transmit vibrations from the vibrato-r to the grate to cause movement of the ash from the zone of combustion through the apertures of the grate and movement of material from above the zone of combustion into the zone of combustion, and means for drawing air into the smoke chamber by way of said air passages into the smoke compartment for mixture with the smoke generated in the combustion chamber and for withdrawing the smoke and air mixture from the smoke compartment.

10. A smoke generator including a casing having side walls and a top, an ash compartment having side walls spaced from side walls of the casing to provide air passages therebetween and having a top and a bottom providing a substantially airtight compartment separated from a smoke compartment in the upper portion of the casing, an open top combustion chamber within the casing and having a wall flaring upwardly and outwardly in encircling relation with an opening in the top of the ash compartment, an apertured grate covering the opening in the ash compartment to control passage of ash from the combustion chamber and air into the combustion chamber, a hopper supported in the smoke compartment of the casing and having a discharge neck suspended within the open top of the combustion chamber for directing flow of wood particles into the combustion chamber, said flow being controlled by rise and fall of the wood particles in the combustion chamber to and from contact with the discharge neck, means for supplying air under pressure to the ash compartment for discharge through the apertures of the grate to maintain a zone of combustion within the combustion chamber, a vibrator fixed to the bottom of the ash compartment, supports attached to opposite side Walls of the ash compartment and carrying guide rails to carry the grate and to transmit vibrations from the vibrator to the grate to cause movement of the ash from the zone of combustion through the apertures of the grate and movement of material from above the zone of combustion into the Zone of combustion, a vibration transmitting member having contact with the grate and extending up through the combustion chamber and into the hopper and having vanes in the discharge portion of the hopper to facilitate movement of said materials, and means for drawing air into the smoke chamber by way of said air passages into the smoke compartment for mixture with the smoke generated in the combustion chamber and for withdrawing the smoke and air mixture from the smoke compartment.

11. In a smoke generator, a combustion chamber having an open top for passage of smoke from the combustion chamber, an ash compartment below the combustion chamber, said combustion chamber having closed sides and an open bottom, an apertured grate member providing an ash outlet from the combustion chamber, vibratable means for supporting the grate member from parts of the ash compartment in covering relation with the open bottom of the combustion chamber, a hopper above the combustion chamber for automatically charging the combustion chamber with particles to be burned, means for supplying air through said apertures into the bottom of the combustion chamber for maintaining a burning of the particles in the combustion chamber above said grate member and below said hopper, said combustion chamber and hopper being connected with said parts of the ash compartment for receiving vibrations therefrom, and a vibrator in connection with said parts of the ash compartment for establishing vibrations to feed the particles from the hopper into the combustion chamber and ash from the combustion chamber through the grate into the ash compartment.

References Cited in the file of this patent UNITED STATES PATENTS 1,360,798 Riley Nov. 30, 1920 1,680,183 Szikla et a1 Aug. 7, 1928 1,939,265 Jordan et al Dec. 12, 1933 2,210,720 Johnson et a1 Aug. 6, 1940 2,317,643 Rogers Apr. 27, 1943 2,640,629 Thomson et al June 2, 1953 2,697,427 Rigali Dec. 21, 1954 2,732,837 Porwancher et al Jan. 31, 1956 2,738,742 Campbell Mar. 20, 1956 

